html {
    width: 100%;
}

body {
    margin: 0;
    padding: 0 0 20px;
    color: #000;
    line-height: 1.5;
    background: #fff;
}

ul {
    list-style-type: none;
}



/* 介绍模块 */
.introduction {
    display: flex;
    flex-direction: column;
    align-items: center;
    /* background-color: rgba(255, 255, 41, 0.301); */
    margin-top: 90px;
}

.introduction_box {
    width: 100%;
}

.introduction_item {
    padding: 20px;
    height: 510px;
}

.item_box {
    width: 100%;
    height: 100%;
    background-color: #f5f7ff;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    padding: 10px;
}

.item_box img {
    width: 60%;
    margin-top: 20px;
}

.item_box img:hover {
    transform: translateY(-10px);
    transform: scale(1.1);
    box-shadow: #000;
    transition: all .5s;
}

.card-body {
    padding: 20px;
    display: flex;
    flex-direction: column;
    align-items: center;

}

/*  */
@media screen and (min-width:750px) and (max-width:991px) {
    .item_box img {
        width: 40%;
        margin-top: 20px;
    }
}

.btn:hover {
    background-color: #3854b0;
    border: 1px solid #fff86d;
}

/* 怎么做模块 */
.function {
    display: flex;
    flex-direction: column;
    align-items: center;
    /* padding: 0 150px; */
    margin-top: 90px;
}

/* 在中等屏幕及以上,加上左右padding:150px */
@media screen and (min-width:970px) {
    .function {
        padding: 0 150px;
    }
}

.p-3 {
    height: 350px;
    background-color: #f5f7ff;
    display: flex;
    flex-direction: column;
    align-items: center;
    margin: 5px;
}

.p-3 img {
    width: 30%;
}

.p-3:hover {
    transform: translateY(-1px);
    box-shadow: 10px 10px 10px #d0cfcf,
        5px -3px 5px #d1d1d1,
        -3px 3px 5px #d5d4d4,
        -3px -3px 5px #c8c7c7;
    transition: all .3s linear;
}

.card-text {
    color: #3f3f3f;
}